(1) Field of the Invention
This invention relates to submarine ejection devices, and more particularly, to an elastomeric ejection device providing variable ejection velocities for ejecting an article such as a missile from a marine vessel.
(2) Description of the Prior Art The launching of missiles, rockets or other articles in marine applications, such as from submarines or ships is typically accomplished by directing fluid under high pressure against the article to be launched. Pressure can be generated through hydraulic systems and/or movable pistons or ram pumps which cause a fluid, usually sea water, to be placed under high pressure. Based on the pressure generated, variable speeds can be produced at which the missile or other article is launched. In the prior art a ram pump design is used for ejecting small devices from a submarine.
Typical shortcomings of current devices for launching missiles or other articles, such as those discussed below, lie in the fact that such launching mechanisms are large, inefficiently consuming space, and loud, threatening covert operations.
The prior art includes a launching device which uses elastomeric energy. Such a device functions by pumping sea water on one side of an elastomer thereby distorting it. When the high pressure water is ported to a launcher, the elastomeric energy pushes water through the system to effect a launch. The problems with such devices is that in order to utilize the optimum stress/strain relationship of an elastomer, each elastomeric shape must be configured to provide a specific device exit velocity. As a result of a marine vessel's requirement to eject devices at two different exit velocities, two elastomeric launcher/ejection systems have been required, one for each velocity. The need for two launch ejection systems results in unacceptable and inefficient space consumption within the vessel.
U.S. Pat. No. 4,527,502 to Schmitt discloses an expelling mechanism for discharge tubes and drain tubes of submarines. The expelling mechanism can be adapted for use in submarines for ejecting a weapon by compressed air and includes a chamber formed with an outlet opening. The chamber is adapted to communicate selectively with a storage container holding compressed gas wherein a discharge valve may be adjusted for controlling velocity via a hydraulic control device. The hydraulic control device includes a cylinder adapted to be filled with hydraulic fluid and a piston reciprocally movable along a stroke within the cylinder.
The cylinder is partitioned into two cylinder chambers via an overflow channel which establishes communication between the cylinder channels and a connecting device connecting the discharge valve with the hydraulic control device. The outlet opening and the overflow channel have cross sections which are variable in dependence of the stroke, respectively, so that the outlet opening increases as the discharge valve moves in the opening direction. The opening velocity of the discharge valve may be controlled, and different respective cross-sections of the overflow channel may be set in dependence of the stroke.
Because a cylinder is used which is activated via a hydraulic mechanism, the Schmitt system is louder than desirable for some covert operations. Also, the Schmitt system is directed to discharging drainage tubes and is probably not powerful enough for launching missiles or the like.
U.S. Pat. No. 5,210,369 to Cassidy discloses a self-actuating slide valve system for launching an article in a fluid environment. An interior channel, in which the article is positioned, is provided with first and second openings in its radial walls for allowing the passage of pressurized fluid into the interior channel. The first opening is located at least partially behind a tail end of the article and the second opening is located forward of the first opening. A sleeve is slidably fitted within a portion of the interior channel and around at least a portion of the article.
The sleeve is movable between at least a first and second position. In the first position, the sleeve prevents the pressurized fluid from entering the interior channel through the first opening. In the second position, the sleeve allows the pressurized fluid to enter the interior channel through the first opening whereby the pressurized fluid can act on the tail end of the article to launch same through an axial opening of the interior channel. The interior channel, the sleeve and the circumferential extremity define a holding volume in communication with the second opening that is adapted to be supplied with the pressurized fluid to maintain the sleeve in its first position and then evacuated of the pressurized fluid to permit the sleeve to attain its second position.
Because a slidable sleeve is used in Cassidy, similar to a cylinder, substantial space is required to achieve the necessary stroke and because of the hydraulics involved, certain covert operations can be threatened.
U.S. Pat. No. 3,857,321 to Cohen discloses a submarine missile launch system. The launch system includes a launch tunnel connecting a launching tube and the outer skin of the vessel through which the missile is adapted to pass. The tunnel is provided with a liner formed from a matrix of resilient finger-like inward projections separated by longitudinal and transverse grooves. The exit end of the matrix is provided with radial inward seal rings adapted to flexibly engage the missile. The fingers are selectively provided with sensors monitoring the movement of the missile, which sensors control a hydraulic counter-torquing system regulating the ejection of the missile. The system shown in Cohen is designed to function with launch systems similar to as described above.
There exists, therefore, a need for an ejection device for use in marine applications which efficiently and covertly uses elastomeric energy for moving fluid under high pressure at variable velocities for use in launching an article.